Sony KP 48S75 Rear Projection Red Haze around objects on screen

Sometimes this can be caused by excessive dust buildup on the lens over the red picture tube, and if you have access to that part of the set, that is where I would start. If it is clean, then you could have the red tube out of focus either due to a bad focus block or if you were lucky, a minor adjustment may fix it. If the set was over 8 years old, I'd consider replacing it with a HDTV model. Check out Consumer Reports latest issue for a start.